1. Field of the Invention
The present invention relates to a lock, and more particularly to a lock driving mechanism for use in a lock.
2. Description of the Related Art
A unique key is used to unlock a corresponding lock. Sometimes, the key has to be changed, which necessitates changing the entire lock. For a common example, a landlord usually has to change door locks when a tenant moves out and a new tenant moves in. Changing the entire lock is not economical, so a lock with a replaceable lock core assembly was invented. When the key is changed, changing the whole lock is not necessary and replacing the lock core is more economical.
With reference to FIGS. 6-8, a lock has a cylindrical housing (60), a lock core assembly (not shown), a round panel (66), a lock driving mechanism (61), a spring (65), a fastening bracket (64) and a latch bolt (not shown).
The cylindrical housing (60) is hollow, is mounted in a door (not shown) and has an inner surface (not numbered) and a receiving hole (601). The receiving hole (601) is defined in the inner surface of the cylindrical housing (60).
The lock core assembly is held rotatably in the cylindrical housing (60), and a corresponding key can be inserted into and rotate the lock core assembly.
The round panel (66) is held rotatably in the receiving hole (601) and has a slot (661). The slot (661) is defined in the round panel (66).
The lock driving mechanism (61) has an inner driving member (62) and an outer driving member (63).
The inner driving member (62) has an inner panel (621) and two inner arms (622). The inner panel (621) has two shoulders (623), a head (624), an inner surface (not numbered) and an outer surface (not numbered). The head (624) protrudes between the shoulders (623) and has two sides (not numbered). The inner surface of the inner panel (621) abuts the round panel (66). The inner arms (622) extend laterally from the two sides of the head (624), insert through the slot (661) of the round panel (66) and is connected with the lock core assembly inside the cylindrical housing (60). When the corresponding key inserts into the lock core assembly, the corresponding key inserts between the two inner arms (622). Further, rotating the corresponding key rotates the inner arms (622) and inner panel (621) in the meanwhile.
The outer driving member (63) has an outer panel (631), a bulge (633) and an outer arm (632). The outer panel (631) has an inner surface (not numbered) and an outer surface (not numbered). The bulge (633) protrudes laterally from the inner surface of the outer panel (631). The outer arm (632) extends laterally from the outer surface of the outer panel (631). When the inner panel (621) rotates, one of the shoulders pushes the bulge (633) to rotate the outer panel (631) and outer arm (632). The inner surface of the outer panel (631) abuts the outer surface of the inner panel (321).
The spring is put around the outer arm (632) of the outer driving member (63) to make the inner surface of the outer panel (631) abut the outer surface of the inner panel (621).
The fastening panel (64) is mounted on the inner surface of the cylindrical housing (60) and defines a through hole (641). The outer arm (632) extends through the through hole (641).
The latch bolt is connected to the outer arm (632) of the outer driving member (63) outside the cylindrical housing (60). The rotary outer arm (632) controls the latch bolt to lock or unlock the door.
Rotating the corresponding key can extend or retract the latch bolt lock. However, in the rotating process of the lock driving mechanism (61), only one of the shoulders (623) pushes the bulge (633) to rotate the outer driving member (63). Thus, a moment imposed by one of the shoulders (623) only concentrates on the bulge (633) but not distributes symmetrically over the outer panel (631). The moment is irregular and cannot make the outer panel (631) rotate smooth.